麻烦英语好的解决
Sugar is so much a part of our modern life that we only really think about it when,for some reason,we cannot obtain it.It has been known to man for at least 3,000 years,but has come into common use only in modern times.Until quite recently it was considered as a medicine and as a luxury for the very rich only.
Sugar is,then,very important to our civilization.But what exactly is it?Of course,most of us recognize sugar immediately as the sweet material which we put in coffee or cakes.This common form of sugar is derived from two plants:the sugarcane (a type of grass which grows to a height of twenty feet) and the sugar beet (which grows under ground).But there are in fact many types of sugar,and the chemist recognizes hundreds of different varieties,each coming from a different source.
About 90% of the sugar is produced as food.Only 10% is used in industry for purposes other than food production.Yet sugar has great possibilities for use as the basis of chemicals.It can even be used for making plastics.In the future these potential uses will certainly be developed more than in the past.
There are many reasons why we should increase the production of sugar.Most important is that it is one of the most highly concentrated of energy foods.Thus sugarcane and sugar beet produce an average of 7,000,000 calories per acre.In this way they have the advantage over potatoes which give only 4,000,000,while the figure for wheat and beans is 2,000,000 each.So three acres of land growing wheat,beans and potatoes give only slightly more energy than one acre of sugar.
16.The heading of Paragraph 1 may be _________.
A.What Sugar Is\x05\x05\x05\x05\x05B.Sugar Through the Ages
C.The Advantages of Sugar\x05\x05\x05D.Present and Future Uses of Sugar
17.The third paragraph emphasizes ________.
A.about 90% of sugar is used as food
B.only 10% is used in industry
C.sugar is used for making plastic
D.future uses of sugar
18.Sugar has been used widely _________.
A.for 3,000 years
B.in modern times
C.quite recently
D.for 300 years
19.How many common forms of sugar are exemplified in this passage?
A.One.\x05\x05\x05B.Two.\x05\x05\x05C.One hundred.\x05\x05\x05D.Several hundreds.
20.The main reason why we should increase the production of sugar is ________.
A.it tastes sweet
B.we can save plenty of land
C.we can get more food
D.it's one of the least highly concentrated of energy foods